Scientists say that since the end of the last ice age about 12,000 years ago and the development of human civilizations, the planet’s long-term average air temperature has never changed more than 1.5 degrees, above a stable average of 14 degrees Celsius.

NCEJ

Within a decade, fossil fuel emissions accumulating in the atmosphere and trapping more of the sun’s energy are expected to warm the planet by 1.5 degrees Celsius.

In a report published in the journal “Science” last September, scientists said that irreversible “tipping points” on the planet are likely to be reached, from the melting of the Greenland ice sheet, which initiates a rise of 7 meters in sea level, to the emission of methane gas, which leads to an increase in the number of planets. The temperature rise accelerates with the thawing of permafrost.

Scientists of the Intergovernmental Panel on Climate Change warned that this could have dire effects on human life and other organisms on the planet, with high rates of extreme weather episodes, rising sea levels, and poor food and water security.

“I can say with a high degree of certainty that civilizations can thrive in a world with a temperature of 14 degrees, but no one can tell us with any degree of certainty that We can thrive in a (much warmer) world because we will never be there.”

Some countries have reportedly suggested at United Nations climate talks that the now highly endangered 1.5C target is unrealistic and should be abandoned in any agreement in Egypt, but others, including the low-lying Maldives, have insisted on keeping this target.

How close is the world to exceeding 1.5°C of global warming, the most ambitious temperature limit set by the 2015 Paris climate agreement? Here’s what Rockstrom, a leading climate scientist, thinks.

IPCC scientists agree that temperatures have now risen by at least 1.2°C above the pre-industrial era, but warming is not spreading evenly across the globe.

On land, temperatures have already warmed about 1.5°C more than they have over larger, colder oceans, and the Northern Hemisphere is getting particularly warm, with Europe seeing a 2°C rise and the Arctic by 3°.

“The effect is exacerbated the further north you go,” Rockstrom said.

Although temperatures are measured in different places around the planet and by a variety of agencies, there are still large gaps in the data.

“You can’t measure every point on Earth,” Rockstrom said. “We don’t record much heat in Antarctica or the North Pole, for example.”

He added that this indicates that “we are underestimating the rise in temperature because we do not have all the data.”

Europe and the Arctic are warming very quickly, in part because more of the planet’s land is warming faster than its oceans in the northern hemisphere, and because of the degree of Earth’s tilt toward the sun.

But Rockstrom said Europe’s success in removing air pollution also plays a role.

In more polluted places, such as large cities in China and India, Rockstrom said, haze effectively reflects some of the sun’s rays into space, like tiny mirrors.

Scientists from the Intergovernmental Panel on Climate Change say air pollution around the world is likely to reduce average global temperature readings by about 0.3 degrees Celsius.

Rockstrom said this means the planet has already warmed by 1.5 degrees Celsius, but the effects of that are yet to be seen.

And he considered, “This is a matter of concern because many countries are trying to quickly transition to green energy derived from renewable resources that provide cheaper and cleaner energy, and also clean the polluted atmosphere.”

“If we clean up the air in Mumbai, New Delhi, and Beijing, we’ll get a boost in heat immediately,” Rockstrom said.

At the current rate at which humans are burning fossil fuels, there are only 7-8 years left to exceed the 1.5°C limits, and to meet the target, countries, companies, and individuals will have to halve their emissions every decade until 2050.

This is a daunting task, Rockstrom said, as global emissions continue to rise today, which indicates that the target may not be met.

He added that the key is to make this overrun as small as possible, hopefully just fractions of a degree, and to try to get temperatures down quickly again.

Machines that pull carbon dioxide out of the air have evolved so that they can be stored underground, but they are still very expensive to operate.

The cheapest way to lower temperatures is to keep the planet’s remaining forests and other natural systems healthy because they naturally absorb carbon dioxide from burning fossil fuels, which helps prevent warming.

Rockstrom said nature has absorbed more than half, 56 percent, of fossil fuel emissions since 1750, half on land and the other half overseas.

But with rates of deforestation and other land degradation rising in many places around the world, nature’s ability to absorb air pollution is declining.

If the world exceeds the 1.5°C warming limit, healthy ecosystems, along with stopping fossil fuel use, may over time help absorb pollution and bring temperatures back down.

But Rockstrom said this “will only work if we don’t destroy nature.”

Rockstrom and other scientists argue that abandoning the 1.5°C targets and moving higher would dramatically increase the risks of food and water shortages, conflict, deadly extreme weather, and other crises, potentially pushing the world beyond dangerous and irreversible tipping points.

To stay safe on the planet, Rockstrom said, “1.5°C is a threshold we cannot cross.”

He added that when this threshold is crossed, “there is certainly a great risk, and we do not want to take it.”

Source

Sky News Arabia